Labor frontbencher Tony Burke agrees with the head of Treasury that government spending must be curbed.
But the opposition's finance spokesman also believes the country has a revenue problem.
Treasury secretary John Fraser warned in a speech last week there is a government spending problem at over 25 per cent of GDP and Australia's triple-A rating could be at risk in the future if government debt is not brought under control.
Mr Burke said since the coalition came to power, expenditure has kicked over the 25 per cent mark.
"Gradually bringing that down ... is something you want to work towards," he told Sky News on Sunday.
At the same time, revenue is well below 25 per cent.
However, he said whether you are trying to improve revenue or reduce expenditure you need to consider the impact on household budgets.
Taxing too hard or pulling back expenditure without considering the future or economic confidence won't work for the economy even if the numbers line up around 25 per cent.
Former Liberal leader John Hewson said Mr Fraser's comments made sense and agreed there is a risk in a five-to-10 year period of a credit rating downgrade if adjustments aren't made to the realities of the budget.
But he said Mr Fraser ignored the fact that both sides of politics have made very large commitments way beyond the four-year budget framework.
These include the national disability insurance scheme, the Gonski school reforms, the NBN and infrastructure spending.
"They are not in the numbers yet, they are unfunded," Dr Hewson told Sky News.
